Apparatus for the control of highway crossing signals



July 1937- J. J. VANHORN 2,085,930

API ARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Original Filed Jan'. 11, 1936 5 Sheets-Sheet 2 IE1? 12/ H l W5 .l:' f x 2 12' 2T 5% 5T I 5 z 15 Ml M B C I 5 c Duo]: lzmrumenzr ZZZ 5T1? 0. 5" Lit-B B Y I V Lp t mz i i 1 59 IR 44 I 51 I T -P i 52 v 40 E E i l I {2, f1! l Ila @12Ws Z 2T 41 5T 1b M] B c a C v Ybaok llzflzlumegzzf TR D SE C I I l B Fly Jame! i f 2 22231 12 BY aim/fa HIS ATTORNEY y 1937- J. J. VANHORN 2,085,930

APPARATUS FOR THE CONTROL O F HIGHWAY CROSSING SIGNALS Original Filed Jan. 11, 1936 3 Sheets-Sheet 3 H la [Elam (5' C Direozional 5 H 620]:

[Izrbmment INVENTOR JamerJ. l azzhorn.

BY fizz/:4; a

HIS ATTORNEY Patented July 6, I937 NITED James J. Vanhorn, Swissvale. Pa, assignor to The Union Switch & Signal Company, Swissvale, ha a corporation of Pennsylvania Application January 11, 1936, Serial No. 58,716 Renewed Ucteber 27, 1936 16 Claims.

My invention relates to apparatus controlled by a train approaching a highway crossing for governing the operation of the highway crossing signal.

A feature of my invention is the provision of novel and improved apparatus controlled by a train approaching a highway crossing for preventing a continued operation of the highway crossing signal in the event the train should stop within the control section, and for restarting the operation of the signal when the train resumes its movement. Other features and advantages of my invention will appear as the specification progresses.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a diagrammatic view of one form of apparatus embodying my invention wherein operation of a highway crossing signal is controlled by a train approaching the intersection from one direction only. Figs. 2 and 3 are diagrammatic views of a second and a third form of apparatus, respectively, for controlling the operation of a highway crossing signal by a train approaching the in,- tersection from one direction only, and both of which forms of apparatus embody my invention. Figs. e, 5, 6 and '7 are diagrammatic views of four difierent forms of apparatus for governing the operation of a highway crossing signal wherein the apparatus in each case is arranged to be effective when a train approaches an intersection from either direction, and each of which forms of apparatus also embodies my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. l, the reference characters la and to designate the rails of a stretch railway over which traffic normally moves in the direction indicated by the arrow, and which rails are intersected by a highway H. A highway crossing signal S is located adjacent the inter-' section. This signal S may take any one of several different forms for highway crossing signals and, as here shown, is an audible signal in the form of an electric bell. The immediate control of signal S is efi'ected through the me dium of a control relay SC the arrangement being suchthat when relay SC is deenergized and its back contact 4 closed current is supplied to signal S over a simple circuit and a warning is sounded. The manner of controlling the relay SC will be described hereinafter.

, The track rails to and lb are divided. by his sulated rail joints 2 to form two track sections 3T and ET which a train traverses in the order named in approaching the highway when travelin the normal direction of traffic. As here 7 shown, the exit end of section 2T is adjacent 5 the highway H. The combined length of these two track sections is sufficient to provide a desired warning period for the signal S prior' to the arrival of a train at the intersection when operation of the signal is initiated as the train 10 enters the section 3T. A wayside station RWS, such for example as a passenger 0r freight station, is located within the track section 3T. Each tract: section is provided with a track circuit which includes a source of current such as a 15 battery 3 connected across the rails at one end of the section, and a track relay R plus a prefix corresponding to the associated section connected across the rails at the other end of the section. i

Three track instruments designated by the 20' reference characters Ml, M2 and M3 are. operatively connected with the rail lb atgselected points for actuation thereof in response to the wheels of a train passing over the point at which the track instrument is located. 'These track,25 instruments are each so designed that it has the characteristic of increasing its resistance in rea spouse to vibration of a train passing the location at which the instrument is attached to the rail. ferent forms and may be rail microphones such as disclosed and claimed in the Letters Patent of .the United States No. 1,834,077, granted December l, 1931, to A. J. Sorenscn. It is deemed sufficient for the present application to point out -35 that such rail microphone comprises an insulat ing housing which contains two spaced metal electrodes with carbon granules in the space between the electrodes. When themicrophone is not vibrated, the resistance between the elec- 40 trodes through the carbon granules is relatively low but when the microphone is vibrated by a passing train and the carbon granulesjare agi-v tated the resistance between the electrodes becomes several times the normal resistance. will be understood, of course, that my invention is not limited to this one form of track instrumerit and other forms may be used.

A relay D is controlled by these track instru-' ments' and to that end is provided with a 'circuit extending from the B terminal of any convenient source of current, such as a battery not shown, through the electrodes'and carbon gr-anof the track instruments M3, M2 and MI in series,windlng of relay D and to the opposite These'track instruments may take dif- 30' terminal C of the same source of current. The parts are so proportioned that when the track instruments Ml, M2 and M3 are all at rest, the flow of current is sufficient to effectively energize relay D and its front contact 9 is closed, but that when at least one of the track instruments is vibrated the flow of current is reduced and the relay is deenergized, or at least is not sufficiently energized, and its front contact 9 is opened. Although only three track instruments are shown, it will be understood that additional instruments may be located at selected points along the track and such additional track instruments connected in the circuit of relay D should it seem desirable to do so.

The signal control relay SC is normally energized over a normally closed circuit passing from the terminal B of the current source over front contacts ii and 'i' of track relays 3TB and 2TB, respectively, winding of relay SC and to the opposite terminal C of the current source. An alternative energizing circuit for relay SC is provided which extends from the B battery terminal over front contact 9 of relay D, back contact 6 of relay 3TB, front contact I of relay 2TB, winding of relay SC and to the C battery terminal. It follows that when both track sections 2T and 3T are unoccupied and the track relays 2TB and 3TB are picked up, or when the section 3T is occupied and section 2T is unoccupied and relay D is picked up, the relay SC is eneregized, but that when section ET is occupied, or when section ET is occupied relay D is down, the relay SC is deenergized. The relay SC is made slightly slow to pick up in character, and consequently it will not pick up in response to pulsating energy which may be supplied to it by relay D momentarily picking up when a train in section 3T is slowly passing over a track instrument.

In order to describe the operation of the apparatusor Fig. 1, it will be assumed that a train enters section 3T, stops at the station RWS and then proceeds over the crossing. As the train approachessection track instrument M3 is vibrated and effectsthe release of relay D, instrument M3 being preferably located just to the rear of the entrance of section 3T. When relay D releases its front contact Si opens a point in the alternative circuit for signal control relay SC. When the train enters section 3T, track relay 3TB releases and the front contact 5 opens the normally closed circuit for signal control relay SC. This latter relay accordingly releases and initiates the operation of signal S by closing back contact i. The track relay 3TB also closes a point the alternative circuit for relay SC at back contact 6, which circuit is now being held open at front contact 53 of relay D. As long as the train continues to advance the relay D will remain deenergized owing to the continued. action of one of the track instruments. When, however, the train is brought to a stop at the station the active track instrument comes to rest and relay D picks up and at its front contact 9 closes the alternative energizing circuit for control relay SC. Relay SC accordingly picks up and stops the operation of signal S. When the train resumes movement, the track instrument in its vicinity (ordinarily the track instrument M!) will again be vibrated and will accordingly again effect the release of relay D, with the result that control relay SC will again be released and operation of signal S restarted. It should be noted that the track instruments are so spaced with respect to the exit end of section 3T that relay D will be maintained released until after the head end of the train enters section 2T and shunts track relay 2TB. With relay 2TB, released the control relay SC will be deenergized and the signal S will be operated until the train passes over the crossing and vacates the section 2T and relay 2TB is again picked up. It is clear that when a train approaching the crossing H continues through the track section 3T without stopping at the station the relay D will remain released and the signal S will continue without interruption to sound the warning.

Referring now to Fig. 2, the track circuits used are similar to those of Fig. l. The track instruments M2 and M3, however, have been dispensed with and an additional relay designated SR added to take their place in the control of the relay SC. The normal energizing circuit for signal control relay SC includes front contacts I5 and ii of track relays 3TB and 2TB, respectively; while the alternative circuit for relay SC includes the front contacts if; and E9 of relays SR and D, respectively, back contact i6 1 of relay 3TB and front contact if of relay ZTR. The relay SR is provided with a pickup circuit passing from terminal B, through the back contact i3 of relay 3TB, back contact E8 of relay D, winding of relay SR, and to terminal C.

A stick circuit for relay SR is also provided and is the same as the pickup circuit except that it includes front contact ii of relay SR instead of back contact E8 of relay D.

When a train enters section 3T, relay 3TB, re-

leases to prepare the pickup circuit for relay SR by closing back contact l3, and at its front con,- tact it opens the normal energizing circuit for relay SC, which releases and closes back contact It to initiate the operation of signal S. As the train approaches track instrument Mi, relay D releases and completes at its back contact E8, the pickup circuit for relay SR, and at front contact i9 opens a further point in the alternative circuit for relay SC. When relay SR picks up, its front contact H closes its stick circuit, while its front contact I0 closes a point in the alternative operating circuit for relay SC. It will be readily seen that if the train proceeds on through section 3T into section 2T without stopping, relay D remains deenergized to hold the alternative circuit for relay SC open until after it is opened at another point by the release of relay 2TB, and operation of signal S under such circumstances, continues until section ET is vacated. the train stops in section 3T, the relay D picks up as soon as the track instrument Mi comes to rest and closes the alternative circuit for relay SC at front contact Hi. The relay SC accordingly picks up and stops the operation of signal S while the train remains standing in section 3T. As soon as movement of the train is again started, the track instrument Ml again becomes operative to effect the release of relay D so that the operation of the signal is again started.

In the form of the invention shown in Fig. 3, the use of relay SR has been dispensed with by dividing the former section 3T into two track circuited sections designated A31 and BST, respectively. The normal energizing circuit for signal control relay SC, in this case, includes the front contacts 25, 26 and 2'5 of the track relays BBTR, A3TR and 2TB, respectively; while the alternative energizing circuit for relay SC includes the front contact 29 of relay D, back Contact 26 of relay If, however,

ASTR, and the front contact 21 of relay ZTR. When a train enters section B3T,relay B3TR releases and at front contact 25 opens the normal energizing circuit for relay SC so that relay SC releases and closes its back contact 25 to start the operation of signal S. Just before the train enters section AST, track instrument Ml becomes active and causes relay D to release and open a point in the alternative circuit for relay SC at front contact 29. A31 track relay A3TR releases, and at its back contact 25 closes a point in the alternative energizing circuit for relay SC and at its front contact 26 opens the normal circuit for relay SC. In this form of the invention, track section ABT will be relatively short, or other track instruments will be spaced along section A3T and interposed in the circuit for relay D in series with track instrument Ml. It will be apparent from the foregoing that so long as the train continues moving relay D will remain deenergized and operation of the signal S will continue, but that if the train stops at the station RWS the relay D will pick up and close the alternative circuit for relay SC at front contact 29, to stop the operation of the signal during the time the train remains standing.

In Fig. 4, the circuits of Fig. l have been modified as required to control the operation ofsignal S by trains approaching the intersection from either direction. The signal control relay SC has been replaced by an interloclc'ng relay IR, a track section iT hasbeen providedfor the stretch of track extending to the left of the highway and a directional relay Y has been added. This track section IT is provided with a track circuit which includes the magnet 6TB of interlocking relay IR. .The track circuits to the right of the highway and the arrangement of the track instruments are similar to those of Fig.1. The normal energizing circuit for the magnet ZTRP of relay IR passes from terminal B, through front contact 36 of relay 3TH, back contact 33 of relay Y, front contact 31 of relay 2TB, winding of magnet 2TRP, and to terminal C. An alternative energizing circuit for magnet ZTRP extends from B terminal over front contact 39 of relay D, back contact 36 of relay 3TB, and thence as before traced.

Relay Y is provided for the purpose of preventing a false operation of signal S occurring when an eastbound train, that is, a train moving from left to right in Fig. 4, has stopped in section ET and then resumes movement. The relay Y is provided with a pickup circuit passing from terminal 7 B, through front contacts 3! and 32 of relays D and 3TB, respectively, back contact lll of'magnet ETR, winding of relay Y, and to terminal 0., Relay Y is also provided with two stickcircuits one of which includes back contact-35 of relay 2TB and the front contact 58 of relay Y, and the other of which includes back contact 5 of relay 3TB, and front contact 48 of relay Y.

When a westbound train, that is, a train moving from r'ght to left in 4, approaches the crossing, the relay Y is not energized since its pickup circuit is held open at front contact 32 of relay 3TB while'the train occupies section 3'1 and is then held open at back contact 46 under the control of magnet 5TB. of the interlocking relay as the train passes over the crossing and occupies section IT, the contact lll being held open due to the interlocking feature of the relay. Hence, a westbound train approaching the inter section will control the magnet ZTRP of the interlocking relay in the same manner as relay S0 of Fig. 1 is controlled and operation of'signal' As the train enters section S over back contact M of magnet ZTRPwill be effected when the train first enters section 3T and V tive circuit and operation of the signals will be discontinued while the train is standing at the station, operation of the signal being restarted as soon as the train again advances. It will be understood that when a westbound train enters section 5T and magnet ETR, isreleased, the contact lda. will not close due to the interlocking feature of the relay and operation of the signal will not be eiiected as the Westbound train recedes from the crossing.

When an eastbound train enters section ET, the a magnet iTR will be deenergized and back contact i la will be closed to initiate the operation of signal S. The back contact ll! of magnet iTR will now be closed and complete the pickup circuit for relay Y and that relay will be picked up. When relay Y picks up it will prepare its stick circuits at its own front contact 38, and at its back contact 38 wfll interrupt both the normal and the alternative energizing circuits for magnet ZTRP. Magnet ZTRP will accordingly become deenergized but its back contact 54 will not close owing to the interlocking feature of the relay IR. When the train enters section ET, the track relay 2TB will be released and at its back a contact will complete one of the stick circuits for relay Y. As the train enters section 3T the relay ETR'Will be released and at its back contact :35 will complete the other stick circuit for relay Y so that relay Y willbe maintained energized as long as the section ST is occupied. When an eastbound train passes over the crossing and vacates section ET, the magnet ETR, will be reenergized and operation of the signal S will be stopped. The eastbound train upon approaching the vicinity of track instrumentMl willcause the relay D to be released but actuationof its contacts at'this time will be without effect since the circuits controlled by relay D are already open at back contact 38 of relay Y and front contact 32 of relay 3TB. Assoon'as the eastbound train vacates section 3T, relay 3TB, will pick up and at back contact 45 stick circuit for relay Y. Relay Y will accordingly release and at its back contact 38 again complete a circuit for magnet 2TB? of the interlocking relay and' enable the interlocking feature of relay IE to again assume its normal position. Were the relay Y not provided, a false open the existing operation of signal S mightresult should an eastbound train stop at the station and then proceed on out of the stretch. For example, when the train stopped at the station in section 3T the relay D would be picked up, and, with contact% deleted from the circuit, would have completed the alternative energizing circuit for magnet QTRP, which would have picked up and released the interlocking feature of the relay. Then'when the train resumed movement the relay D, would have been again releasedand at its front contact 39 would have interrupted the circuitfor magnet ZTRP and its back contact fi l would. be closed since the interlocking feature has now beenreleased and thus operation of signal S would result while this train moved away from the crossing' out of section 3T. With the back contact 38 of relay Y included in the energizingcircuits' for the magnet ZTRP, such undesired operation of signal S is prevented.

In Fig. 5, the circuit arrangement shown in Fig. 2 has been modified as required to control the operation of the signal S during train movements in either direction. The interlocking relay IR. and relay Y are again used in the same manner as in Fig. 4. Likewise the relay SR is used as in Fig. 2. The normal energizing circuit for magnet ZIRP of interlocking relay IR includes front contact to of relay 3TB, back contact 53 of relay Y, and front contact Q? of relay ETR. This circuit will be recognized as being identical to the normal energizing circuit for magnet ZTRP as used in Fig. l. The alternative energizing circuit for magnet 2TB? of interlocking relay IR includes front c ntacts 5c and ii of relays SR and D, respectiveiy, back contacts it and 58 of relays STR and Y, respectively, and the front contact All of relay ETR. This alternative energizing circuit for magnet 2TB will be recognized as the same as provided for the signal control relay SC of Fig. 2, except for the inclusion of back contact 58 of relay Y.

The pickup circuit for relay Y includes front contacts 5! and 32 of relays D and 3TB, respectively, and the back contact 66 of magnet 5TB of the interlocking relay. While the stick circuits relay Y include the front contact 58 of relay Y and the back contacts and of relays and 3TB, respectively. These circuits will be recognized as being similar to those provided for relay Y in Fig. i. In view of the foregoing, it will be readily apparent that westbound trains moving through sections 3']? and ET will cause the magnet 2TB? to control the operation of signal S in identica"'y ti same manner that the signal is controlled relay SC of Fig. 2, and cperatl n of the signal will be discontinued as soon as section 2T is vacated for the reasons clearly set forth in the discussion of the operation given in connection with Fig. 4. It will also be seen that as an eastbound train passes through the stretch, the relay Y will be picked up and will remain energized until section 3T is vacated, and will accordingly prevent magnet QTRP being energized by relay D picking up when an eastbound train makes a stop in section It be evident that when eastbound train enters section 3T the pickup circuit for relay SR will be prepared by the closure of back contact d3 of track relay 3TB, and will be subsequently completed at back contact ltd of relay D when the latter relay releases. i'he operation of relay SE at this time, however, is without eifect as the alternative circuit for magnet 2TB? in which front contact 58 of relay SR is included is already open at the back contact 58 of relay I. W en the train vacates section relay again up and at its back contacts 33 and 65 opens the stick circuits for relays SR and Y, respectively, and these relays accordingly release. When back contact 58 of relay Y again closes, the normal energizing circuit for magnet ETRP is again established.

In the form of the invention illustrated in Fig. 6, the track circuits are identical to those employed in Figs. 4 and 5. The rail lb of section ET is also provided with a track instrument Ml arranged at a location opposite the station RWS as in the former arrangements, and in addition, is provided with directional track instruments TW and TE. These latter two track instruments are of the wellknown type which actuate their contacts as a vehicle or train passes over them in one direction only. Associated with the track instrument TW is a stick relay W having a pick up circuit which passes from terminal B through back contact 63 of relay 3TB, wires '43, 13a and T30, contact N3 of track instrument TW closed only by trains moving in a westward direction, winding of relay W, and to terminal C. The stick circuit for this relay is the same as that traced except that it includes front contact 12 of relay W instead of contact 18 of track instrument TV]. A stick relay E is associated with the track instrument TE and is provided with a pickup circuit passing from terminal B through contact 52 of track instrument TE, closed only by trains moving in an eastward direction, winding of relay E, and to terminal C. The stick circuit for relay E includes back contact .53 of relay 3TB, wires l3 and 13b and the front contact 6i of relay E. The relay D is normally deenergized and is provided with an energizing circuit passing from terminal B through back contact 63 of relay 3TB, wires 2'3, 13a and 730, the track instrument Mi, winding of relay D, and to terminal C. The normal energizing circuit for magnet ZTRP includes front contacts 55 and 5'3 of relays 3TB and 2TB, respectively; while a first alternative energizing circuit magnet ZTRP includes front contacts ii and of relays W and D, respectively, back contact 66, of relay 3TB, and front contact 5? of relay 2TB; and a second alternative energizing circuit for magnet ZTRP includes front contacts 6i and 5? of relays E and ZIR, respectively.

When a westbound train enters section 3T, track relay 3TB is released and at its front contact interrupts the normal circuit for magnet 'ZTRP, which accordingly releases and closes the the contact 69 of relay D opens the alternative energizing circuit for magnet ZTRP prior to the closing of front contact ii of relay W when that relay is picked up over contact 16 of track instrument TW, with the result that magnet 2TB? is not energized at this time. tinues its movement uninterruptedly into section ET, the track relay 2TB is released and opens the energizing circuits for magnet ETRP at front contact 5? beforerelay D picks up, and, therefore, operation of signal S continues without interruption until the section 2T is vacated. Since the relay'W is retained energized over its stick circuit as long as a westbound train occupies section 3T, it follows that if the train stops at the station RWS and relay D is picked up due to track instrument Ml not being vibrated the first alternative circuit for magnet 2TB? is completed and operation of signal S is discontinued as long as the train remains standing at the station, but as soon as it again advances relay D is again released with the result that operation of signal S is restarted.

When an eastbound train enters section l'I of Fig. 6, magnet lTR releases and at its back con tact G la closes an operating circuit for the signal S. When the train enters section 2T relay 2TB,

releases and opens the energizing circuit for magnet ZTRP but operation of the signal S is stopped as soon as the train vacates section ET and magnet ITR is energized because the contact 54 con- If the train conr trolled by magnet ZTRP is held open by the interlocking feature of relay IR. When the eastbound train enters section 3T, relay 3TB, releases and at back contact $6 closes a point inthe first alternative energizing circuit for magnet 2TRP. Relay D may pick up when the train first enters section 3T and remain energized until the train is close to the track instrument MI but the closing of front contact 89 of relay D is without effect since the first alternative circuit for magnet ZTRP is held open at front contact H of relay W, which relay can only be energized by the closing of contact iii of track instrument TW, and which instrument closes its contact it only when a westbound train is moving over it. From the foregoing, it will be seen that in the absence of any control by track instrument TE, which will be shortly referred to, the magnet ZTRP remains deenergized until an eastbound train vacates section ST, and, therefore, no loss of interlock of relay IR. results and no false operation of signal S, such as described in connection with Fig. 4, occurs in the event an eastbound train stops at the station RW S.

The track instrument TE and its associated relay E are provided to prevent operation of signal S occurring in case a westbound train stops at station RWS and then backs out of section 3T. When a train moving east encounters track instrument TE its contact 62 closes the pickup circuit for relay E. Relay E on picking up completes its own stick circuit at front contact 6i and com pletes at its front contact 61 the second alternative energizing circuit for magnet ETRP. Magnet ZTRP accordingly becomes energized when a train moving east passes the track instrument TE and releases the interlocking feature of relay IR. When a train moving east vacates section ET the track relay 3TB again picks up and at its front contact 85 reestablishes the normal energizing circuit for magnet ZTRP and at its back contact 53 opens the stick circuit for relay E and thus the apparatus is restored to its normal position as the train moves cast out of section 3T.

As previously mentioned, the instrument TE and its associated stick relay E are provided to enable a westbound train making a station stop to then back off section 3T without again initiating the operation of signal S, and this feature of my invention will now be described. When a westbound train enters section 3T and stops at station RWS operation of signals is discontinued in the manner already described. If now this train starts to back out of section 3T track instruments ME and TE are operated, and relay D is released and opens contact 59 in the first alternative circuit for magnet ZTRP. At the same time, contact $2 of track instrument TE closes the pickup circuit for relay E. Relay E picks up and at front contact iii closes the second alternative circuit for magnet ZTRP, so that even though the first alternative circuit for this magnet is opened, its second alternative circuit is closed while section 3T is occupied and deenergizing of magnet ZTRP is prevented. Operation of signal S as a result of a westbound train backing out of section ET is therefore avoided.

In the form of the invention shown in Fig. '7, the entire portion of the control territory to the right of highway H is combined into a single track section T, which is provided with one vibratory track instrument MI and two directional track instruments TW and TWI, actuated by westbound trains only. The energizing circuit for relay D in this case passes from terminal B through back contact I5 of track relay TR, normally closed contact 84 of track instrument TWI, wires 83 and 830, track instrument MI, winding of relay D, and to terminal C. The pickup circuitfor relay W is the same as that traced for relay D up to wire 83c, thence through contact 80 of the track instrument TW, winding of relay W, and to terminal C. The stick circuit for relay W is the same as the pickup circuit, except that it includes front contact 82 of relay W instead of contact 80 of track instrument TW. Magnet ZTRP of the interlocking relay IR is normally energized over a circuit including the front contact E6 of relay TR, and has an alternative energizing circuit including the front contacts BI and I9 of relays W and D, respectively, and the back contact E6 of relay TR. 1

When a westbound train enters section T, the track relay TR releases and at its front contact I6 interrupts the normal circuit for magnet ZTRP, which accordingly releases and closes its back contact I'd to initiate the operation of signal 5. At the same time relay D becomes energized as a result of the closure of back contact I5 of relay TR and at its front contact 19 closes one point in the alternative energizing circuit for magnet ZTRP. As the train approaches the vicinity of the railway station RWS, the track instruments M! and TW are operated, the track instrument MI effecting the release of relay D so that contact 79 in the alternative circuit for magnet ETRP is again opened, while the contact 8Ilof track instrument TW is closed and relay W becomes energized. When relay W picks up, its front contact 8! closes another point in the alternative circuit for magnet ZTRP. If the train stops before reaching the track instrument TWI the relay D again picks up and completes the alternative energizing circuit for magnet ZTRP at front contact I9, to stop the operation of signal S while the train remains standing at the station. As soon as the train resumes movement, however, the track instrument MI again becomes effective to release relay D so that operation of the signal is again initiated. Before the train has receded from the track instrument MI a sufficient distance to enable relay D to again pick up, the head end of the train encounters track instrument TWI so that its contact 84 opens the stick circuit for relay W. This relay accordingly releases and at its front contact 8| interrupts the alternative circuit for magnet 2TRP, so that operation of the signal S is then continued until the track section T is vacated.

When an eastbound train enters section IT, magnet ITR will release and at its back contact Ma initiate the operation of signal S inthe usual manner. As soon as the train vaca-tes section IT, the magnet ITR will again pick up and discontinue the operation of signal S. It will be seen that although relay D will be actuated as the eastbound train passes through section T, the operation of the relay D will exercise no control over the alternative energizing circuit for magnet ZTRP for the reason that this circuit will remain open at the back contact SI of the relay W. It will be seen, therefore, that whether the eastbound train stops at station RWS or not, operation of signal S will not occur after section IT has been vacated.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: V

1. In combination, a stretch of railway track intersected by a highway and including a track section equipped with a track relay, a highway crossing signal located at the intersection, a control relay for said signal, train actuated means encountered by a train approaching the intersection for modifying the condition of said control relay as required to effect the operation of said signal and to maintain the condition of said control relay so modified only while movement of the train continued within said section, and means including the track relay of said section for placing said control relay under control of said train actuated means.

2. In combination, a stretch of railway track intersected by a highway and including a track section equipped with a track relay, a highway crossing signal located at the intersection, a control relay for said signal, train actuated means encountered by a train approaching the intersection for modifying the condition of said control relay as required to effect the operation of said signal and to maintain the condition of said control relay so modified only while movement of the train continues, means including the track relay of said section for placing said control relay under the control of said train actuated means irrespective of the direction of movement of, a train, and means for preventing said train actuated means from exercising any control over said relay when actuated by a train receding from the intersection.

3. In combination, a stretch of railway track divided into a plurality of track sections each provided with a track relay and one section of which is intersected by a highway, a highway crossing signal at the intersection, a control relay for said signal normally, energized over a circuit including front contacts of said track relays, a track instrument at a station location actuated only while a train in the vicinity of such location is moving, a second circuit for said control relay including a back contact of one of said track relays, and an auxiliary relay under con trol of said track instrument and having a contact included in said second circuit.

4. In combination, a stretch of railway track intersected by a highway and including a track section provided with a track circuit including a track relay, a highway crossing signal at the intersection, a control relay for said signal normally energized over a circuit including a front contact of said track relay, a track instrument at a station location within said stretch actuated only while a train in the vicinity of such location is moving, a second circuit for said control reiay including a back contact of. said track relay, and an auxiliary relay under control of said track instrument and having a contact included in said second circuit.

5. In combination, a stretch of railway track comprising two track sections each equipped with a track relay and the exit end of one section of which is intersected by a highway, a signal at the intersection having an operating circuit, a signal control relay for holding said operating circuit open and itself included in a normally closed circuit including a front contact of one of said track relays, a second circuit for said signal control relay including afront contact of one of said track relays and a back contact of the other of said track relays, an auxiliary relay having a front contact included in said latter circuit, and a circuit for said auxiliary relay including a series of track instruments spaced along one of said sections and successively operated by a train approaching the intersection to maintain said auxiliary relay released so long as the movement ofv the train continues while within such section and until the train enters the other of said sections.

6. In combination, a stretch of railway track intersected by a highway and including two track sections each equipped with a track circuit including a track relay, a highway crossing signal located at the intersection, a control circuit for said signal, train actuated means encountered by a train approaching the intersection for mod ifying the condition of said control circuit as required to effect the operation of said signal and to maintain said control circuit so modified only while movement of the train continues, means including the track relay of the first encountered of said sections for placing said control circuits under the control of said train actuated means, and a contact of the track relay of the second encountered of said sections for thereafter caussaid control circuit to continue to efiect the operation of said signal until the second encountered of said sections is vacated.

'7. In combination, a stretch of. railway track intersected by a highway and including a track section provided with a track circuit including a track relay, a highway crossing signal located at the intersection, an operating circuit for said signal, a control relay for said circuit having a normally closed circuit including a front contact of said track relay, an alternative circuit for said control relay including a back contact of said track relay closed when a train approaching the intersection enters said section, means for preventing the closure of said alternative circuit by such track relay until the head end of the train vacates said section providing the train moves uninterruptedly through said section, and other means for opening a common point in both circuits for said control relay as soon as the head end of the train vacates said section.

8. In combination, a stretch of railway track intersected by a highway and including a track section provided with a track circuit including a track relay, a highway crossing signal located at the intersection, an operating circuit for said signal, a control relay for said circuit having a normally closed circuit including a front contact of said track relay, an alternative circuit for said control relay including a back contact of said track relay closed when a train approaching the intersection enters said section, means for preventing the closure of said alternative circuit by such track relay until the head end of the train vacates said section providing the train moves uninterruptedly through said section, and other means for causing a point in said alternative circult to be opened as soon as the head end of the train arrives at a predetermined point along said stretch.

9. In combination, a stretch of railway track intersected by a highway, a track section within said stretch provided with a track circuit including a track relay, a highway crossing signal at the intersection, a control relay for said signal normally energized over a circuit including a front contact of said track relay, a first track instrument located within said section, other track instruments arranged on opposite sides of said first track instrument, a first auxiliary relay under the control of said first track instrument, a second auxiliary relay placed under the joint control of said other track instruments by said track relay when said section becomes occupied and a second circuit for said control relay including a back contact of said track relay and contacts of said auxiliary relays respectively.

10. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, an operating circuit for said signal, and train actuated means asscciated with a selected section of said stretch and efiective when a train approaching the intersection enters said selected section for modifying the condition of said operating circuit as required tooperate the signal and to maintain the condition of the operating circuit so modified only while movement of the train continues.

11. In combination, a stretch of railway track intersected by a. highway, a highway crossing signal located at the intersection, an operating circuit for said signal, a first train actuated means associated with the stretch and efiective when actuated by a train approaching the intersection for modifying the condition of said operating circuit as required to operate the signal, and other train actuated means associated with the stretch and effective to maintain the condition of the operating circuit so modified only while movement of the train continues.

12. In combination, a stretch of railway track intersected by a highway, a highway crossing signallocated at the intersection, an operating circuit for the signal, a first train actuated means associated with the stretch and effective when a train approaching the intersection reaches a fixed point for modifying the condition of the operating circuit as required tooperate the signal, and a series of train actuated devices one at each of several selected locations along the stretch and successively encountered by the train after passing said fixed point and each device efiective to maintain the condition of the operating circuit so modified only when the train in the vicinity of its location is moving.

13. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, an operatingcircuit for said signal, train actuated means associated with a selected portion of said stretch and effective when encountered by a train in approaching the intersection for modifying the condition of said operating circuit as required to operate the signal and to maintain the condition of the operating circuit so modified only while movement of the train continues, and other train actuated means for placing said operating circuit under the control of the first mentioned train actuated means when the train enters said selected portion of the stretch.

14. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, an operating circuit for said signal, train actuated means associated with the stretch to one side of the intersection and effective when actuated by a train for modifying the condition of the operating circuit as required to operate the signal and to maintain the condition of the operating circuit so modified only while movement of the train continues, directional means efiective when energized for preventing said train actuated means from exercising any control over the operating circuit, and means governed by a train approaching the intersection from the side opposite said one side for energizing said di ectional means.

15. In combination; a stretch of railway track formed into a first, a second and a third track section and each provided with a track circuit; said second section intersected by a highway, a highway crossing signal located at the train in the vicinity of the instrument is moving, an alternative circuit for said secondmagnet including a back contact of the track relay associated with the thirdsection and a front contact of the auxiliary relay, a directional relay having a pickup circuit including a back contact r of said first magnet, stick circuit means for the directional relay including back contacts of the two track relays in parallel, and a back contact of said directional relay interposed in said alternative circuit.

16. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a control relay for governing the operation of the signal, a first track instrument located at a station along the stretch to one side of the highway and effectively actuated only when a train in the vicinity of the station is moving, other track instruments one on each side of the first track instrument and said other instruments each efiectively actuated only when a train is moving in the direction to approach the intersection, a first auxiliary relay controlled by said first track instrument and deenergized when the instrument is actuated, a second auxiliary relay controlled by said other track instruments and energized when the instrument more remote from the intersection is actuated and deenergized when the instrument nearer the intersection is actuated, and a circuit for at times governing said control relay and including a front contact of each of said auxiliary relays. 7

JAMES J. VANHORN. 

